Self-propelled trenching machine



FIG. 1 is a perspective view from the left front side of the self-propelled trenching machine showing my new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a front view thereof; and

FIG. 6 is a rear view thereof. 

The ornamental design for a self-propelled trenching machine, substantially as shown and described. 